Current-collecting device



(No Model.)

L. GUTMANN.

CURRENT COLLECTING DEVICE.

No. 599,781. Patented Mar. 1, 1898.

Wifflefifiefir 2730672321 M MMM w I W 6mm UNITED STATES PATENT OEEIcE.

LUDIVIG GUTMANN, OF PEORIA, ILLINOIS.

CURRENT-COLLECTING DEVICE.

SPECIFICATION forming part of Letters latent No. 599,781, dated March 1,1898.

Application filed April 26, 1897.

T0 aZZ whom it may concern.-

Be it known that I, LUDWIG GUTMANN, a citizen of the United States,residing at Peoria, in the county of Peoria and State of Illinois, haveinvented a certain new and useful Improvement in Current-CollectingDevices, (Case No. 94,) of which the following is a full, clear,concise, and exact description, reference being had to the accompanyingdrawings, forming a part of this specification.

My invention relates to current-collecting devices, and moreparticularly to improvements in gauze brushes for dynamo-electricmachines, the object of my said invention being to increase theefficiency and durability of said brushes.

It is the common experience that gauze brushes admirably serve thepurpose of collecting current when the machine operates in a faultlessmanner. If, however, an open circuit develops or the pole-pieces of thedynamo or motor are very close together, sparking is liable to occur atthe least irregularity in the operation of the dynamo, which frequentlydestroys the commutator and rapidly consumes the brushes. Owing to thesmall sizes of wire employed in gauze it is evident that gauze brushesare quickly destroyed when used with a defective armature, sinceimmediately upon the occurrence of an open circuit or defectivecommutation violent sparking at the segments takes place and the edgesof the brushes are instantly fused. The fine wire of the gauze is thuschanged at the contact-surface into hard globular masses of copper andthe brush loses its flexibility. In consequence of this the life of thebrush is considerably reduced, since the fused portions must necessarilybe removed in order to secure the requisite pliability in the brush andprovide good metallic contact. The improved brush of my invention, whichavoids these difficulties, is provided with a gauze body having anexternal covering or coverings formed of laminae or leaves, preferablyof metal having a high melting-point and offering comparatively greatresistance to the flow of current. In many forms 'of brushes it is founddesirable to insulate the gauze from the external leaves, which also iscontemplated by my said invention.

Serial No. 633,870. (No model.)

I likewise show an improved brush-holder extension adapted to beinserted in the brushholder of the dynamo and receive short lengths ofthe brush, which consists in an extension adapted to be inserted withinthe dynamo brushholder and a clamp attached thereto wherein the shortlengths of brush are held for use.

My invention will be more readily understood by reference to theaccompanying drawings, in which Figures 1, 2, and 3 illustrate differentforms of my improved gauze brush. Fig. 4 is a View, partially insection, of the brush-holder extension. Fig. 5 illustrates means forsecuring direct connection between the brush and brush-holder arm. Figs.6, 7, 8, and 9 indicate the preferred mode of forming the gauze bodyportions of the brushes.

Like lettters indicate like parts throughout the different views.

In Fig. 1 is shown one form of my improved brush, consisting of a bodyportion a, formed of wire-gauze,upon which are disposed a num ber ofsupplemental strips or leaves I), of conducting material, connected withthe gauze at the upper end of the brush 0. A strip of insulatingmaterial cl may be placed between and electrically separate the saidbody portion and supplemental leaves for the greater portion of theirlength. I preferably employ a gauze formed of fine copper wire for thebody of my brush and a resistance metal, such as German silver orphosphor-bronze, for the supplemental leaves, although other conductingmaterial, such as iron or copper, may be found desirable. The body andsupplemental portions of the brush are secured together by immersing theupper ends thereof in a bath of solder, which firmly unites the same,making the end of the brush solid and adapting it to be clamped in thebrush-holder or extension.

A recess a may be provided in the end of the brush, as shown in thedrawings.

A modification of the brush described is illustrated in Fig. 2, whereinwires Z) of comparatively large cross-section are substituted for theleaves or strips 1), and a reinforcingplate 11 preferably of brass, issuperposed upon the wires, which extends to within a short distance ofthe lower end of the brush, the said wires answering the purpose of theleaves or strips of resistance metal.

A third form of modification of my improved brush or current-collectoris shown in Fig. 3, differing from the one first described only in theprovision of supplemental leaves of conducting material upon both thefront and back of the brush, one or both of which may either be partlyinsulated or in contact with the gauze body portion.

By the use of the composite conductors above described a high degree ofconductivity and great flexibility are secured in the brush, whilesparking is materially reduced at the commutator, since thearmature-coil connected with the brush at its leaving edge has theresistance of the superposed strips of resistance metal connected incircuit therewith, and, furthermore, the life of the brush is greatlylengthened by reason of the fact that all sparking is transferred fromthe gauze to the supplemental leaves of the brush, which are less likelyto be fused. Thus, referring to Fig. l, current from segment e of thecommutator,which is represented as passing from beneath the brush, mustflow through the leaves of resistance metal b,while the current from thesegments e and e is conducted through the copper-gauze portion a,thegauze being protected by the resistance metal from the destructiveeffect of any sparking which brush-holder g of the dynamo-electric ma-vchine, wherein it is adjustable, and a knub 0 f may be provided upon oneof the jaws,

adapted to receive the recess 0' in the end of the brush and hold saidbrush securely in po- Sition.

Fig. 5 illustrates a clamp h attached to the upper end of the brush, thesaid clamp hava ing a flexible conductor h, adapted to be con necteddirectly with the brush-holder arm 712. By employing this construction Iam enabled to secure perfect connection between the brush andbrush-holder arm,which frequently is found to be poor by reason of anintervening film of oil or loosely-fitting parts.

The remainder of the figures of the drawings indicate the preferredmanner of manufacturing my improved gauze brush. This consists inwinding upon a mandrel k or of suitable size and shape, suficientwiregauze to form, when properly compressed, a brush of the desiredsize. The gauze thus employed may be of the necessary width to form oneor a number of brushes, the width of the gauze representing the lengthof the brush or brushes manufactured therefrom. When the gauze is thusformed in coils or rolls of suitable size, it is passed between rollerswhich shape it to the'required cross section of the brush, the gauzethereafter being cut to the desired length. For example, the gauze Z iswound upon a round mandrel k to the thickness of one-quarter of an inchif it be desired to manufacture a brush one inch in width by one-halfinch in thickness,

the width of the gauze in this instance representing the length of thecompleted brush. When thus wound, the roll of gauze is passed betweenhorizontal and vertical rollers m m and n 'n, as shown in Figs. 8 and 9,which serve to compress the roll of gauze somewhat and give it thedesired cross-section. The plate or mandrel shown in Fig. 7 with gauzeWound thereon is adapted for the manufacture of a brush much wider andthinner than the one above considered, it being desirable to proportionthe mandrel tothe cross-section of the brush.

Gauze brushes manufactured in this manner are compact and admirablyadapted to the uses for which they are intended. The gauze body portionsare cut to the requisite length and, when desired, are provided with thesupplemental leaves or strips of resistance metal and insulatingmaterial, and one end of the composite brush is dipped in molten solder,which secures the parts together, as previously described.

I do not desire to be understood as limiting myself to the preciseconstructions shown or to the materials specifically mentioned in theabove specification; but,

Having now described means forpracticing my invention, what I claim asnew, and desire to secure by Letters Patent, is

1. The combination in a brush for dynamoelectric machines, with a gauzebody portion a formed of conducting material, of a superposed stratum ofsupplemental conducting leaves or laminae Z), and an electrical union 0joining said conductors at one extremity of the brush, substantially asdescribed.

2. In a brush for dynamo-electric machines, the combination with a bodyportion of gauze conductor, of a strip of insulating material, and asuperposed stratum of conducting material electrically connected withthe gauze at one extremity of the brush, substantially as described.

3. In a brush for dynamo-electric machines, the combination with a gauzebody portion a, of a strip of insulating material d, and supplementalleaves or strips 1) formed of conducting material of comparatively highre sistance superposed upon the gauze and an electrical union 0 joiningthe conductors at one extremity of the brush, substantially asdescribed.

4. In a composite brush fordynamo-electric machines, the combinationwith a gauze body portion formed of low-resistance conducting material,of a strip of insulating material extending for a portion of the lengththereof, and supplemental leaves or strips of conducting material ofcomparatively high resistance superposed thereon and electrically unitedto the gauze at one extremity of the device, substantially as described.

5. In a brush for dynamo-electric machines, the combination with a bodyportion formed of copper gauze, of an insulating-strip covering saidgauze for a portion of its length, a supplemental strip or strips formedof a metal of comparatively high resistance disposed thereon, and ametallic connection uniting the supplemental conductor or conductors andthe gauze at one extremity of the brush, substantially as described.

6. In a brush-holder extension, the combination with a shank adapted tobe inserted in the brush-holder of the dynamo and adjustably securedtherein, of jaws or clamps adapted to receive the brush, aknubprovidedwithin said jaws fitting a recess or opening formed in the brush, andmeans for clamping the brush between the jaws, substantially asdescribed.

7. In a brush-holder extension, the combination with a shank g adaptedto be removably adjusted Within the brush-holder of the dynamo, of jawsor clamps f adapted to receive the brush, and a knub f or equivalentpart provided upon said extension adapted to fit a recess or openingformed in the brush, and means for clamping the brush between the jaws,substantially as described.

In witness whereof I hereunto subscribe my name this 21st day of April,A. D. 1897.

LUDIVIG GUTMANN.

Witnesses L. J. CARLOCK, G. T. NICHOLS.

